Caption: Chest muscles. Computer artwork of an oblique anterior view from below of some of the muscles (red) of the chest, showing their attachment to the bones of the ribcage and back. These are the serratus anterior muscles, which attach to the first eight to nine ribs and the medial border of the scapula (shoulder blade). They act to pull the scapula forwards during an action such as swinging an arm forward. The scapula is shown in semi-transparent view to show the location of the muscles underneath it. Also shown here are the bones of the ribcage and spine. The clavicles (collar bones) across the top of the torso are not shown in this view.